scholarly journals The production of auxin by dying cells

2021 ◽  
Author(s):  
A Rupert Sheldrake
Keyword(s):  
Cell Death ◽  
Organic Matter ◽  
Acetic Acid ◽  
Vascular Plants ◽  
Hydrolytic Enzymes ◽  
Living Cells ◽  
Tracheary Elements ◽  
Auxin Production ◽  
Dying Cells ◽  
Indole 3 Acetic Acid

Abstract In this review, I discuss the possibility that dying cells produce much of the auxin in vascular plants. The natural auxin, indole-3-acetic acid (IAA), is derived from tryptophan by a two-step pathway via indole pyruvic acid. The first enzymes in the pathway, tryptophan aminotransferases, have a low affinity for tryptophan and break it down only when tryptophan levels rise far above normal intracellular concentrations. Such increases occur when tryptophan is released from proteins by hydrolytic enzymes as cells autolyse and die. Many sites of auxin production are in and around dying cells: in differentiating tracheary elements; in root cap cells; in nutritive tissues that break down in developing flowers and seeds; in senescent leaves; and in wounds. Living cells also produce auxin, such as those transformed genetically by the crown gall pathogen. IAA may first have served as an exogenous indicator of the presence of nutrient-rich decomposing organic matter, stimulating the production of rhizoids in bryophytes. As cell death was internalized in bryophytes and in vascular plants, IAA may have taken on a new role as an endogenous hormone.

Is there a relationship between tracheary element formation and lignification in soybean (Glycine max var. Wayne) callus cultures?

1986 ◽  
Vol 64 (11) ◽  
pp. 2716-2718 ◽  
Author(s):  
A. Raymond Miller ◽  
Lorin W. Roberts
Keyword(s):  
Acetic Acid ◽  
Glycine Max ◽  
Time Course ◽  
Lignin Content ◽  
Tracheary Element ◽  
Dry Weight ◽  
Naphthaleneacetic Acid ◽  
Tracheary Elements ◽  
Element Number ◽  
Indole 3 Acetic Acid

The possible relationship between tracheary element number and lignin content was studied in cultured soybean (Glycine max L. var. Wayne) cotyledon callus. Callus initiated on 4.5 μM 2,4-dichlorophenoxyacetic acid contained 3.0 × 104 tracheary elements per gram fresh weight and 41 μg lignin per milligram dry weight after 10 days incubation, and these values did not vary significantly after two subsequent transfers (7 days each) to a medium containing 0.1 μM α-naphthaleneacetic acid and 0.01 μM kinetin. Transfer of this callus to a medium supplemented with 60 μM indole-3-acetic acid and 0.5 μM kinetin resulted in significant increases in tracheary element number and lignin content (290 and 56%, respectively). A time-course study revealed that both tracheary element number and lignin content reached a maximum 5 to 6 days after transfer to the medium containing indole-3-acetic acid and kinetin. However, when total callus lignin content was plotted against total tracheary element number, no statistically significant relationship was found. The formation of lignin not associated with tracheary elements may have been a factor. These results indicate that the induction of tracheary element formation and lignification in soybean callus have similar hormonal requirements, but lignification occurs independently of tracheary element formation in this system.

scholarly journals Auxin Production Is a Common Feature of Most Pathovars of Pseudomonas syringae

1998 ◽  
Vol 11 (2) ◽  
pp. 156-162 ◽  
Author(s):  
Eric Glickmann ◽  
Louis Gardan ◽  
Sylvie Jacquet ◽  
Shafik Hussain ◽  
Miena Elasri ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Pseudomonas Syringae ◽  
Related Species ◽  
Gene Encoding ◽  
Iaa Production ◽  
Auxin Production ◽  
Indole 3 Acetic Acid

We investigated indole-3-acetic acid (IAA) production by 57 pathovars of Pseudomonas syringae and related species. Most of those analyzed produced IAA, especially in the presence of tryptophan. Eight strains produced high IAA concentrations in the absence of Trp. The iaaM and iaaH genes of P. savastanoi pv. savastanoi were detected in a limited number of strains only, including the eight above-mentioned strains. Thus, IAA synthesis in most assayed strains of P. syringae and related species does not involve genes highly similar to iaaM and iaaH. In contrast, the iaaL gene encoding an IAA-lysine synthase was detected in most pathovars, and was often found on plasmids.

scholarly journals Cell Death Triggered by the YUCCA-like Bs3 Protein Coincides with Accumulation of Salicylic Acid and Pipecolic Acid But Not of Indole-3-Acetic Acid

2019 ◽  
Vol 180 (3) ◽  
pp. 1647-1659 ◽  
Author(s):  
Christina Krönauer ◽  
Joachim Kilian ◽  
Tina Strauß ◽  
Mark Stahl ◽  
Thomas Lahaye
Keyword(s):  
Cell Death ◽  
Acetic Acid ◽  
Salicylic Acid ◽  
Pipecolic Acid ◽  
Indole 3 Acetic Acid

scholarly journals Bacillus spp.: potent microfactories of bacterial IAA

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7258 ◽  
Author(s):  
Shabana Wagi ◽  
Ambreen Ahmed
Keyword(s):  
Acetic Acid ◽  
Plant Growth ◽  
Growth Conditions ◽  
Plant Growth Promoting Bacteria ◽  
Bacterial Isolates ◽  
Production Potential ◽  
Iaa Production ◽  
Auxin Production ◽  
Growth Promoting ◽  
Indole 3 Acetic Acid

Background Auxin production by bacteria is one of the most important direct mechanisms utilized by plant growth-promoting bacteria (PGPB) for the betterment of plants naturally because auxin is a plant friendly secondary metabolite synthesized naturally by bacteria, and hence improves the growth of associated plants. So, the current study focuses on bacterial synthesis of Indole-3-acetic acid (IAA) for plant growth improvement. Methods In the current study, the PGPB were selected on the basis of their auxin production potential and their growth promoting attributes were evaluated. Indole-3-acetic acid producing potential of two selected bacterial isolates was observed by varying different growth conditions i.e., media composition, carbon sources (glucose, sucrose and lactose) and different concentrations of precursor. Influence of various physiological factors (temperature and incubation time period) on IAA production potential was also evaluated. Results Both the bacterial strains Bacillus cereus (So3II) and B. subtilis (Mt3b) showed variable potential for the production of bacterial IAA under different set of growth and environmental conditions. Hence, the IAA production potential of the bacterial isolates can be enhanced by affecting optimum growth conditions for bacterial isolates and can be used for the optimal production of bacterial IAA and its utilization for plant growth improvement can lead to better yield in an eco-friendly manner.

scholarly journals An Evolutionarily Primitive and Distinct Auxin Metabolism in the Lycophyte Selaginella moellendorffii

2020 ◽  
Vol 61 (10) ◽  
pp. 1724-1732
Author(s):  
Shutaro Kaneko ◽  
Sam David Cook ◽  
Yuki Aoi ◽  
Akie Watanabe ◽  
Ken-Ichiro Hayashi ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Vascular Plants ◽  
Metabolite Profile ◽  
Marchantia Polymorpha ◽  
Plant Growth And Development ◽  
Functional Diversification ◽  
Metabolic Genes ◽  
Selaginella Moellendorffii ◽  
Indole 3 Acetic Acid ◽  
Iaa Biosynthesis

Abstract Auxin is a key regulator of plant growth and development. Indole-3-acetic acid (IAA), a plant auxin, is mainly produced from tryptophan via indole-3-pyruvate (IPA) in both bryophytes and angiosperms. Angiosperms have multiple, well-documented IAA inactivation pathways, involving conjugation to IAA-aspartate (IAA-Asp)/glutamate by the GH3 auxin-amido synthetases, and oxidation to 2-oxindole-3-acetic acid (oxIAA) by the DAO proteins. However, IAA biosynthesis and inactivation processes remain elusive in lycophytes, an early lineage of spore-producing vascular plants. In this article, we studied IAA biosynthesis and inactivation in the lycophyte Selaginella moellendorffii. We demonstrate that S. moellendorffii mainly produces IAA from the IPA pathway for the regulation of root growth and response to high temperature, similar to the angiosperm Arabidopsis. However, S. moellendorffii exhibits a unique IAA metabolite profile with high IAA-Asp and low oxIAA levels, distinct from Arabidopsis and the bryophyte Marchantia polymorpha, suggesting that the GH3 family is integral for IAA homeostasis in the lycophytes. The DAO homologs in S. moellendorffii share only limited similarity to the well-characterized rice and Arabidopsis DAO proteins. We therefore suggest that these enzymes may have a limited role in IAA homeostasis in S. moellendorffii compared to angiosperms. We provide new insights into the functional diversification of auxin metabolic genes in the evolution of land plants.

scholarly journals Indole-3-Acetic Acid Biosynthesis inColletotrichum gloeosporioides f. sp.aeschynomene

1998 ◽  
Vol 64 (12) ◽  
pp. 5030-5032 ◽  
Author(s):  
M. Robinson ◽  
J. Riov ◽  
A. Sharon
Keyword(s):  
Acetic Acid ◽  
Colletotrichum Gloeosporioides ◽  
In Vitro Assay ◽  
Acid Biosynthesis ◽  
Major Pathway ◽  
Vitro Assay ◽  
Auxin Production ◽  
Feeding Experiments ◽  
Indole 3 Acetic Acid

ABSTRACT We characterized the biosynthesis of indole-3-acetic acid by the mycoherbicide Colletotrichum gloeosporioides f. sp.aeschynomene. Auxin production was tryptophan dependent. Compounds from the indole-3-acetamide and indole-3-pyruvic acid pathways were detected in culture filtrates. Feeding experiments and in vitro assay confirmed the presence of both pathways. Indole-3-acetamide was the major pathway utilized by the fungus to produce indole-3-acetic acid in culture.

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